THE FERN'S PLACE IN NATURE. 49 



ing of filaments ; sexual reproduction consisting of the union 

 of two similar cells, both of which are equally active in the pro- 

 cess. Product of reproduction a zygospore. Contains five 

 classes, of which the first four are " algae." * 



1. ZOOSPORE^E. (Water-net, Sea Lettuce, etc.) 



2. DESMIDIACE^E. (Desmids.) 



3. DIATOMACE^E. (Diatoms.) 



4. ZYGNEMACE^E. (Pond Scums.) 



5. ZYGOMYCETES. (Black Moulds.) 



133. III. Oophyta Plant body varying from a loosely 

 united colony of cells through filamentous forms to a well- 

 developed thallus ; sexual reproduction accomplished by the 

 union of a small active cell (antheridium} with a larger passive 

 cell (pogoniutn). Product of reproduction an oospore. Con- 

 tains seven classes.t of which the first three and the last are 



1. ZOOSPORE^E. (Volvox, etc.) 



2. CEDOGONIE/E. (Small fresh-water algae.) 



3. VAUCHERIACE^:. (Green Felts.) 



4. SAPROLEGNIACE.E. (Water-mould ; Fish-fungus.) 



5. ENTOMOPHTHORE/E. (Fly-fungus.) 



6. PERONOSPORE^:. (Downy Mildew; White Rust.) 



7. FUCACE^E. (Rock-weed and other brown algae.) 



1 34. IV. Carpophyta. Plant body varying from poorly 

 developed filaments (in parasitic forms) to a highly developed 

 thallus (Floridece), or with a distinct leafy axis (Characece) 

 sexual reproduction accomplished by the union of an active cell 

 or cells produced in the antheridium, and a larger passive cell 

 (here called carpogoninni) ; product of reproduction a sporo- 

 carp (spore-fruit), usually containing numerous spores sur- 

 rounded by a more or less complicated envelope of sterile cells. 



1882 (2cl edition, p. 53) the shortening of the terms to Zygospora, Oospora, 

 and Carpospora. Dr. Bessey in his " Essentials" (1884) completed the uni- 

 formity by changing all so as to end in phyta. To complete the series, I 

 have adopted Spermaphyta for the highest group. 



* The last four are often grouped together as " conjugatce" differing 

 from the first in possessing stationary instead of motile reproductive cells. 



t The 3d, 4th, 5th, and 6th form the class Cosloblastece of Bessey's Botany. 

 4 



